SpringBoot入门-JPA（三）

什么是JPA

JPA全称Java Persistence API.JPA通过JDK 5.0注解或XML描述对象－关系表的映射关系，并将运行期的实体对象持久化到数据库中。

pom.xml

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>1.5.2.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>

    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
        <java.version>1.8</java.version>
    </properties>

    <dependencies>
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <version>1.16.18</version>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-data-jpa</artifactId>
        </dependency>

        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>6.0.6</version>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>

apllication.yml

server:
  port: 8080

spring:
  datasource:
    driver-class-name: com.mysql.jdbc.Driver
    username: root
    password: root
    url: jdbc:mysql://localhost:3306/test?useUnicode=true&characterEncoding=utf8&characterSetResults=utf8&serverTimezone=GMT%2B8

  jpa:
    hibernate:
      ddl-auto: update
    show-sql: true

Dao

import com.vast.entity.Account;
import org.springframework.data.jpa.repository.JpaRepository;
/** JPA中提供的crud的方法，可以直接进行调用。泛型中Account指要操作的数据库对应的实体类；Integer指的是该实体类对应的主键的类型 */
public interface IAccountDao extends JpaRepository<Account,Integer> {
}

Controller（请求方式是Restfull风格）

package com.vast.controller;

import com.vast.dao.IAccountDao;
import com.vast.entity.Account;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.web.bind.annotation.*;

import java.util.List;

@RestController
@RequestMapping("/account")
public class HomeController {
    @Autowired
    private IAccountDao accountDao;

    @Value("${my.name}")
    private String name;
    @Value("${my.age}")
    private int age;

    @GetMapping("/home")
    public String homePage(){
        return name.concat("13__" + age);
    }

    @GetMapping("/{id}")
    public Account getAccountById(@PathVariable(value = "id") int id){

        return accountDao.findOne(id);
    }

    @GetMapping("/list")
    public List<Account> getAccounts(){
        return accountDao.findAll();
    }

    @RequestMapping(value = "",method = RequestMethod.POST)
    public String postAccount(@RequestParam(value = "name") String name,
                              @RequestParam(value = "money") double money) {
        Account account = new Account();
        account.setName(name);
        account.setMoney(money);

        Account saveAccountResult = accountDao.save(account);

        return saveAccountResult.toString();
    }

    @PutMapping("/{id}")
    public String updateAccountById(@PathVariable (value = "id") int id,
                                    @RequestParam(value = "name",required=false) String name,
                                    @RequestParam(value = "money",required=false) double money){

        Account account = new Account();
        account.setName(name);
        account.setMoney(money);
        account.setId(id);

        Account account1 = accountDao.saveAndFlush(account);

        return account1.toString();
    }

}